The Scientific Data Are Clear:
Soy Protein Provides Heart Health Benefits
Soy protein lowers blood cholesterol levels according to years of scientific evidence1-10 and the conclusions of the U.S. Food and Drug Administration (FDA) and health agencies in Canada11 and 11 other countries.12
Nevertheless, the FDA recently announced it is proposing to change the existing heart health claim for soy protein. The possible change to a “qualified” health claim indicates that while the FDA believes the scientific evidence still supports consumption of soy protein as a means of lowering blood cholesterol levels, it recognizes there is some inconsistency in the results of recent clinical trials. However, no adverse effects were observed in these studies.
Such inconsistency is not at all unexpected as there is no nutrition research area where clinical studies have produced entirely consistent findings. This is true even for the effects of sodium on blood pressure13,14 and calcium on bone mineral density15,16 and yet reducing the intake of sodium is routinely recommended by nutritionists as a means of reducing risk of heart disease and increasing calcium intake as a means of preventing osteoporosis .
The Soy Nutrition Institute (SNI) intends to provide data and comment to the FDA during the 75-day comment period that was opened by the FDA with the announcement of the possible change to the soy protein health claim. In addition to commenting on the cholesterol lowering effects of soy protein, other benefits will be highlighted in SNI comments.
While the mechanism behind the ability of soy protein to lower cholesterol levels in humans remains elusive, it has been observed that soyfoods can help to lower cholesterol levels by replacing commonly consumed sources of dietary protein because of the favorable change in the fatty acid content of the diet.1 In fact, the cholesterol lowering effect of soybean oil was recently recognized by the FDA in the form of a heart health claim.17 Furthermore, there is intriguing evidence that there may be components of soybeans and soyfoods aside from the fat and protein that favorably affect a number of coronary heart disease risk factors.18-21
Soyfoods provide ample amounts of high-quality protein, so regardless of someone’s risk of developing coronary heart disease, adding soyfoods to the diet makes nutritional sense.22 Importantly, the nutrition community recognizes that to markedly reduce cholesterol levels and coronary heart disease risk requires adopting a comprehensive dietary approach. Because of
their varied nutritional and health attributes, soyfoods and soy protein have been key components of comprehensive dietary approaches that have led to dramatic reductions in cholesterol.23-28
Therefore, from a public health perspective, regardless of any possible change to the existing soy protein heart health claim the clinical evidence indicates that soyfoods can make important contributions to heart-healthy diets.
For more information about the nutrition and health attributes of soyfoods visit www.thesoynutritioninstitute.com.
1. Jenkins DJ, Mirrahimi A, Srichaikul K, et al. Soy protein reduces serum cholesterol by both intrinsic and food displacement mechanisms. J Nutr. 2010;140:2302S-11S.
2. Zhan S, Ho SC. Meta-analysis of the effects of soy protein containing isoflavones on the lipid profile. Am J Clin Nutr. 2005;81:397-408.
3. Harland JI, Haffner TA. Systematic review, meta-analysis and regression of randomised controlled trials reporting an association between an intake of circa 25 g soya protein per day and blood cholesterol. Atherosclerosis. 2008;200:13-27.
4. Anderson JW, Bush HM. Soy protein effects on serum lipoproteins: A quality assessment and meta-analysis of randomized, controlled studies. J Am Coll Nutr. 2011;30:79-91.
5. Benkhedda K, Boudrault C, Sinclair SE, Marles RJ, Xiao CW, Underhill L. Food Risk Analysis Communication. Issued By Health Canada’s Food Directorate. Health Canada’s Proposal to Accept a Health Claim about Soy Products and Cholesterol Lowering. Int Food Risk Anal J. 2014;4:22 | doi: 10.5772/59411.
6. Tokede OA, Onabanjo TA, Yansane A, Gaziano JM, Djousse L. Soya products and serum lipids: a meta-analysis of randomised controlled trials. Br J Nutr. 2015;114:831-43.
7. Yang B, Chen Y, Xu T, et al. Systematic review and meta-analysis of soy products consumption in patients with type 2 diabetes mellitus. Asia Pacific J Clinical Nutr. 2011;20:593-602.
8. Hooper L, Kroon PA, Rimm EB, et al. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2008;88:38-50.
9. Reynolds K, Chin A, Lees KA, Nguyen A, Bujnowski D, He J. A meta-analysis of the effect of soy protein supplementation on serum lipids. Am J Cardiol. 2006;98:633-40.
10. Weggemans RM, Trautwein EA. Relation between soy-associated isoflavones and LDL and HDL cholesterol concentrations in humans: a meta-analysis. Eur J Clin Nutr. 2003;57:940-6.
11. Summary of Health Canada’s Assessment of a Health Claim about Soy Protein and Cholesterol Lowering. Bureau of Nutritional Sciences Food Directorate Health Products and Food Branch. https://www.canada.ca/en/health-canada/services/food-nutrition/food-labelling/health-claims/assessments/summary-assessment-health-claim-about-protein-cholesterol-lowering.html.
12. Xiao CW. Health effects of soy protein and isoflavones in humans. J Nutr. 2008;138:1244S-9S.
13. Graudal NA, Hubeck-Graudal T, Jurgens G. Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterol, and triglyceride. The Cochrane database of systematic reviews. 2011:CD004022.
14. Lelong H, Galan P, Kesse-Guyot E, Fezeu L, Hercberg S, Blacher J. Relationship between nutrition and blood pressure: a cross-sectional analysis from the NutriNet-Sante Study, a French web-based cohort study. Am J Hypertens. 2015;28:362-71.
15. Lanou AJ, Berkow SE, Barnard ND. Calcium, dairy products, and bone health in children and young adults: a reevaluation of the evidence. Pediatrics. 2005;115:736-43.
16. Tai V, Leung W, Grey A, Reid IR, Bolland MJ. Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ. 2015;351:h4183.
17. Qualified Health Claim Petition – Soybean Oil and Reduced Risk of Coronary Heart Disease (Docket No. FDA-2016-Q-0995). https://www.fda.gov/downloads/Food/IngredientsPackagingLabeling/LabelingNutrition/UCM568508.pdf.
18. Pase MP, Grima NA, Sarris J. The effects of dietary and nutrient interventions on arterial stiffness: a systematic review. Am J Clin Nutr. 2011;93:446-54.
19. Li SH, Liu XX, Bai YY, et al. Effect of oral isoflavone supplementation on vascular endothelial function in postmenopausal women: a meta-analysis of randomized placebo-controlled trials. Am J Clin Nutr. 2010;91:480-6.
20. Li Y, Zhang H. Soybean isoflavones ameliorate ischemic cardiomyopathy by activating Nrf2-mediated antioxidant responses. Food & Function. 2017.
21. Liu XX, Li SH, Chen JZ, et al. Effect of soy isoflavones on blood pressure: A meta-analysis of randomized controlled trials. Nutrition, metabolism, and cardiovascular diseases : NMCD. 2012;22:463-70.
22. Hughes GJ, Ryan DJ, Mukherjea R, Schasteen CS. Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: Criteria for evaluation. J Agric Food Chem. 2011;59:12707-12.
23. Jenkins DJ, Jones PJ, Frohlich J, et al. The effect of a dietary portfolio compared to a DASH-type diet on blood pressure. Nutrition, Metabolism CVD: NMCD. 2015;25:1132-9.
24. Jenkins DJ, Jones PJ, Lamarche B, et al. Effect of a dietary portfolio of cholesterol-lowering foods given at 2 levels of intensity of dietary advice on serum lipids in hyperlipidemia: a randomized controlled trial. JAMA. 2011;306:831-9.
25. Jenkins DJ, Kendall CW, Faulkner D, et al. A dietary portfolio approach to cholesterol reduction: combined effects of plant sterols, vegetable proteins, and viscous fibers in hypercholesterolemia. Metabolism. 2002;51:1596-604.
26. Jenkins DJ, Kendall CW, Faulkner DA, et al. Long-term effects of a plant-based dietary portfolio of cholesterol-lowering foods on blood pressure. Eur J Clin Nutr. 2008;62:781-8.
27. Jenkins DJ, Kendall CW, Marchie A, et al. Effects of a dietary portfolio of cholesterol-lowering foods vs lovastatin on serum lipids and C-reactive protein. JAMA. 2003;290:502-10.
28. Jenkins DJ, Kendall CW, Marchie A, et al. Direct comparison of a dietary portfolio of cholesterol-lowering foods with a statin in hypercholesterolemic participants. Am J Clin Nutr. 2005;81:380-7.
About the Soy Nutrition Institute
The mission of the Soy Nutrition Institute is to identify soy and health research priorities, provide evidence-based information on the impact of soybeans and soy components on human health through a variety of education and outreach efforts and, as funds may be available, facilitate the development and funding of targeted research projects.
The Soy Nutrition Institute is a collaborative organization begun in 2004 through the initiative of the United Soybean Board and soy industry leaders, including global corporations and national associations. Members meet at least twice annually to review and discuss research related to soy and health. Emerging issues are examined with presentations from experts in the field. Literature reviews and primary research are commissioned by SNI, as funding allows.